Method of communicating information and corresponding device and system

ABSTRACT

A communication circuit supports a first communication protocol and a second communication protocol that is different from the first communication protocol. A number of signals include first signals conveying first information messages and second signals conveying second information messages. The first information messages include a repetitive message having fixed repeated content and the second information messages include a non-repetitive message having variable content. The first signals and the second signals are transmitted via the communication circuit using the first communication protocol for the first signals and the second communication protocol for the second signals.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to Italian Patent Application No.102018000008489, filed on Sep. 11, 2018, which application is herebyincorporated herein by reference.

TECHNICAL FIELD

The description relates to communication techniques and, in particularembodiments, to a method of communicating information as well as acorresponding device system and operation mode.

BACKGROUND

The impact of communications in the present world is impressive.Widespread use of communication technologies and devices provides peoplewith unprecedented opportunities to interconnect, and a new era wherethings are connected and communicate has just begun: to that effect thedesignation Internet of Things (IoT) has been created and is commonlyused to indicate a communication segment where objects are part of anetwork configured to exchange data. These objects may pertain todifferent applications and the amount of data exchanged may vary from anapplication to another.

Data may be sensitive and people using technologies have a right in thatdata of private nature shall be protected, a principle that is beingincreasingly recognized as a priority at the human level. For instance,to this aim, the European Union has adopted in May 2018 a set of rulesto be adopted and applied by member States, referred as the General DataProtection Regulation.

Data may also carry information that facilitates correct operation of anapplication, for instance to provide a service, to grant human securityand for other purposes.

In this framework, a main function of a communication act, that isconveying with success a message from a sender to a receiver is animportant goal to pursue.

Various physical communication media have been proposed and used inorder to facilitate effectively sending and receiving information indifferent application scenarios: wireless communication, power linecommunication, coaxial cable communication, sound wave communicationsare exemplary of such communication media.

For a physical communication medium, the knowledge of the communicationchannel and the associated noise scenarios where a sender and a receiverare expected to operate plays an important role in designing acommunication protocol able to facilitate successful communication atthe physical layer level as desired.

A physical communication protocol can be implemented in a device—digitalor analog—and include one or both of sender (transmitter) TX andreceiver RX functions. Such devices are commonly referred to as modems.

The communication channel and noise scenario may be known to thecommunication designer. Oftentimes this may not be the case for variousreasons.

For instance the modem may be a general-purpose modem (not “tailored” toa specific channel).

Also, while the physical communication medium may be known per se, theoperational scenario cannot be predicted.

As an example one may consider a power line communication scenario wherethe loads connected to the power line may be various and change,possibly many times during a day.

Under these circumstances, the modem designer may rely on the knowledgeavailable and select, based on his or her experience and analysis, thefeatures of physical communication protocols with the aim of providingas wide as possible a coverage of the expected scenarios with a simpledesign.

As communication techniques improve, a communication network comprisingmodems implementing at a certain time a certain physical communicationprotocol may evolve towards a communication network comprising modemssupporting at least one different physical communication protocol thatis believed to offer more reliable communications in the generalcontext. If the network is a large one, replacing a network supportingan “old” protocol with a network supporting a “new” protocol may taketime. Also a transition phase may be involved where the two protocols,the old one and the new one, should co-exist.

SUMMARY

One or more embodiments can contribute in providing an improvedsolution.

One or more embodiments may relate to a corresponding device (a modem,for instance).

One or more embodiments may relate to a corresponding communicationsystem.

One or more embodiments may relate to a method of operating such acommunication system.

One or more embodiments may relate to a corresponding signal.

The claims are an integral part of the technical teaching providedherein in respect of the embodiments.

One or more embodiments may provide a communication system supporting(at least) two physical protocols: a first physical protocol, used forrepetitive messages, and a second physical protocol, used fornon-repetitive messages.

In one or more embodiments, the first physical protocol may include afirst modulation (for instance a S-FSK modulation) and the secondphysical protocol may include a second modulation (for instance a PSK ora QAM modulation).

In one or more embodiments, the longest message length of the firstphysical protocol may be shorter than the longest message length of thesecond communication protocol.

In one or more embodiments, the number of possible messages that canadopt the first physical protocol may be lower than the number ofmessages that can adopt the second physical protocol.

In one or more embodiments, only a portion of the messages using thefirst physical protocol is part of the set of repetitive messages.

In one or more embodiments, the first physical protocol may comprise asingle carrier protocol and the second physical protocol may comprise amulticarrier protocol.

In one or more embodiments, the repetitive messages may be transmittedas a function of a predetermined period.

In one or more embodiments, the two physical protocols may coexist in atime division multiplexing (TDM) scheme.

In one or more embodiments, the non-repetitive messages may betransmitted between (for instance interleaved to) repetitive messages.

BRIEF DESCRIPTION OF THE DRAWINGS

One or more embodiments will now be described, by way of example only,with reference to the annexed figures, wherein:

FIG. 1 is a representation of a frame format comprising two physicalprotocols;

FIG. 2 is a representation of a dual-protocol modem;

FIGS. 3 and 4 are exemplary of a possible application scenario ofembodiments;

FIGS. 5 and 6 are exemplary of a possible application scenario ofembodiments;

FIGS. 7 and 8 are exemplary of a possible application scenario ofembodiments; and

FIGS. 9 and 10 are exemplary of a possible application scenario ofembodiments.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

In the ensuing description, one or more specific details areillustrated, aimed at providing an in-depth understanding of examples ofembodiments of this description. The embodiments may be obtained withoutone or more of the specific details, or with other methods, components,materials, etc. In other cases, known structures, materials, oroperations are not illustrated or described in detail so that certainaspects of embodiments will not be obscured.

Reference to “an embodiment” or “one embodiment” in the framework of thepresent description is intended to indicate that a particularconfiguration, structure, or characteristic described in relation to theembodiment is comprised in at least one embodiment. Hence, phrases suchas “in an embodiment” or “in one embodiment” that may be present in oneor more points of the present description do not necessarily refer toone and the same embodiment. Moreover, particular conformations,structures, or characteristics may be combined in any adequate way inone or more embodiments.

The references used herein are provided merely for convenience and hencedo not define the extent of protection or the scope of the embodiments.

By way of introduction to a detailed description of exemplaryembodiments, one may refer to a solution as disclosed U.S. Pat. No.8,743,908 B2, providing for the possible coexistence of two physicalprotocols in a same frame F, namely an “old” protocol OP used for aframe preamble and a “new” packet protocol NP. Coexistence of the two isbased on the fact that the new protocol NP prepends (that is, adds tothe beginning) its packet with the synchronization information of theold protocol. A similar approach is adopted in the HomePlug AV powerline standard (see, for instance,https://en.wikipedia.org/wiki/HomePlug), in the Hybrid mode, to allowcoexistence with old HomePlug 1.0.1 devices.

According to the concept underlying the scheme represented in FIG. 1, asa result of detecting the prepended synchronization information, the oldprotocol (OP) modems, will be busy to try to decode a packet they cannotunderstand and leave the physical communication medium free for the newprotocol (NP) modems. Essentially, the concept underlying the schemerepresented in FIG. 1 involves using the new protocol by graduallyreplacing the old one with the new one. Such an approach may facilitatecoexistence of two protocols during a transition period, with the newprotocol expected to completely replace the old one in the long run.

When considering two different physical communication protocols, say,Protocol 1 and Protocol 2, one of the two protocols may perhaps begenerally “better” than the other: for instance Protocol 2 may begenerally better than Protocol 1. However, in certain applicationscenarios, Protocol 1 may be better than Protocol 2 as Protocol 1 hasparticular characteristics: that is, while, in the general case,Protocol 2 may be better than Protocol 1, a limited scenario portion mayexist where Protocol 1 may be better than Protocol 2.

By way of explanation, one may consider, as an of example:

a first communication protocol based on Frequency Shift Keying (FSK),such as Spread Frequency Shift Keying, S-FSK: as known to those of skillin the art, S-FSK is a FSK scheme involving frequencies widely spacedapart,

a second communication protocol based on another modulation such asPhase Shift Keying (PSK) modulation or Quadrature Amplitude Modulation(QAM).

At present, it is generally acknowledged and expected that—in a generalcontext—PSK or QAM modulations will provide better performance. Anindirect confirmation of this is provided by the number of communicationspecification that adopt PSK and/or QAM modulations.

Specifications such as, for instance:

the whole IEEE 802.11 series (wireless LAN),

Long Term Evolution (LTE) wireless for mobile,

IEEE 802.15.4 (Zigbee),

G3-PLC, PRIME, HomePlug AV and HomePlug AV2 standards (power linecommunication),

IEC 14443 (RFID),

BlueTooth

are exemplary of the tendency of communication experts to select PSKand/or QAM modulations.

On the other hand, it is noted that a protocol using S-FSK modulationmay have interesting robustness properties in particular scenarios, suchas in the presence of in-band narrow-band interference.

For example, in the case of a single carrier S-FSK system using twofrequencies, if an interferer falls in the signal band at one of the twoS-FSK frequencies, a S-FSK receiver may use the non-corrupted frequencyto facilitate correct reception of a message even if the interferer ismuch stronger than the signal itself. Conversely, in the case of a PSK-or QAM-based single carrier system a strong narrow-band interfererfalling in the signal band may cause the PSK or QAM receiver to beexposed to data corruption.

The advantage of S-FSK modulation discussed above may be perceived andappreciated (only) in a particular scenario—such as un-balanced SNRswithin the two tones. This explains why keeping active two protocols maynot be justified, at least at first sight: a priori, one cannot expectto be able to know at what time the scenario favorable to the S-FSKmodulation will occur. Also, techniques which may predict and estimatenoise may be cumbersome to introduce.

Consequently, the above example referred to S-FSK modulation bearswitness to the possibility of using two communication protocolsconcurrently and taking the benefits of both is an area still deservinginvestigation.

In the following the general case of two different communicationprotocols, namely Protocol 1 and Protocol 2, will be considered by wayof non-limiting example, being otherwise understood that the discussion(and the embodiments as well) can be extended to more than twoprotocols.

Also, for the sake of simplicity and ease of explanation, one of the twoprotocols, hereafter referred as Protocol 2, may be deemed to be“generally” better than the other protocol, hereafter referred asProtocol 1, being otherwise understood that, in certain particularapplications scenarios, Protocol 1 may be better than Protocol 2.

These circumstances may occur in different application scenarios wherethe advantages associated with the embodiments may be appreciated.

Those of skill in the art will otherwise appreciate that the scenariosdiscussed herein are merely exemplary and do not limit the scope of theembodiments; also, they are pretty different and—a priori—not linked toone another.

In this latter respect, it will be appreciated that features and/orelements discussed in connection with each one of these exemplaryscenarios can be transposed to the other scenarios so that a certainfeature and/or element discussed in connection with a certain one thesescenarios is not to be understood as linked by way of necessity (only)to that scenario.

For instance, a first possible application scenario to which embodimentsmay apply (as discussed in the following in connection with FIGS. 3 and4) is a solar power generation system.

Such a solar system may comprise several (photovoltaic—PV) solar panelsSP1, SP2, . . . , SPk and an inverter I. The inverter I and the panelsSP1, SP2, . . . , SPk may include each a communication unit including amodem. The modem may be a DC power line modem capable of communicatingsignals by re-using the underlying DC voltage lines or via a differentphysical medium.

Another exemplary application scenario to which embodiments may apply(as discussed in the following in connection with FIGS. 5 and 6) is ahouse monitoring system. The system may include a local unit LU, acentral unit CU and several monitoring points HM1, HM2 . . . HMn.

The monitoring points may be placed in a home HP or outside. Themonitoring points HM1, HM2, . . . , HMn may include cameras or sensorsand a communication unit. The communication unit of each monitoringpoint may include a modem that communicates to a modem placed in thelocal unit LU the information obtained via sensors associated to themonitoring points HM1, HM2 . . . HMn. These modems may be AC power linemodems capable of communicating signals by re-using the electrical linesin the home or via a different physical medium.

The central unit CU may coincide with the local unit LU or may belocated elsewhere in the case of remote monitoring; in that case thelocal unit could forward to the central unit a part or all theinformation gathered from the monitoring units.

Still another exemplary application scenario to which embodiments mayapply (as discussed in the following in connection with FIGS. 7 and 8)is a traffic monitoring system.

The system may include a series of observation points 1, 2, . . . , S.Each observation point may be equipped by different sensors or camerasand a communication unit. The observation points 1, 2, . . . , S may beconnected to a central unit C that gathers the traffic information andthe communication units in the observation points may include modemsthat communicate traffic information with a modem in the central unit C.The modems may be wireless modems or power line modems.

Still another exemplary application scenario to which embodiments mayapply (as discussed in the following in connection with FIGS. 9 and 10)is a “smart” city illumination system. The system may include a seriesof lampposts LP1, LP2, . . . , LPk, . . . , LPn and an illuminationcontroller IC. Both the illumination controller IC and the lamppostsLP1, LP2, . . . , LPk, . . . , LPn may include a communication unit, andat least for certain ones of the lampposts LP1, LP2, . . . , LPk, . . ., LPn, a sensor set. The communication units may include modems that mayuse the available AC power line backbone that connects the differentlampposts or a different physical medium.

One or more embodiments may be based on the recognition that certaintypes of communications—such as those which may occur, for instance, inthe exemplary scenarios discussed in the foregoing—may include a subsetof messages that are repetitive, that is convey the same informationseveral times.

Such messages can be in the form “all is ok” or “continue to do it” or“I'm here” or “keep synchronized”. For sure, other repetitive messageswith different semantics can be envisaged, such messages being primarilyconfirmatory messages, whose informative content (entropy) isessentially related to the fact that the message is sent (and received)confirming that a certain situation/condition persists and/or is not (tobe) changed.

For instance, in the first exemplary application scenario discussedabove (solar panel systems), the inverter I can periodically send to thepanels SP1, SP2, . . . , SPk a repetitive message of the kind: “powerproduction active”, which may be sent both for starting and continuingpower generation. If the message is sent periodically, absence of therepetitive message after a certain period may indicate that powerproduction should be halted.

Conversely, non-repetitive messages may be variable in time, in thatthey may convey contents which vary over time. For instance, thesemessages may include panel temperature statistics, panel voltage orpanel inclination to improve solar power capturing or similar quantitiesthat may vary several times and with different granularity during theday. Essentially, non-repetitive messages convey informative contentproper beyond the mere fact that the message is sent/received.

In the second exemplary application scenario discussed in the foregoing(a house monitoring system) a repetitive message could be “all is ok, nohousebreaking”. Again, this is a message whose informative content isessentially related to the fact that the message is actually sent (andreceived).

In a house monitoring system, non-repetitive messages may be morevariable in time and content. Such non-repetitive messages may conveyinformative content proper beyond the mere fact that the message issent/received, for instance by conveying information on external and/orinternal house atmosphere monitoring (temperature, pressure) for use,for instance, in house air-conditioning, soil moisture monitoring toprovide the proper irrigation to an external garden, internal controland use of the household appliances. Also here, non-repetitive messagesconvey informative content proper beyond the mere fact that the messageis sent/received.

In the third exemplary application scenario discussed in the foregoing(a traffic monitoring system) a repetitive message could be “no caraccident” or “traffic unit (for instance the traffic lights) operatingas expected” or “traffic unit activated”. Once again, these are messageswhose informative content is essentially related to the fact that theyare sent (and received).

Non-repetitive messages can again be more variable messages in time,whose contents may relate for instance to noise level parameters (forinstance an index of the car concentration in the urban trafficmonitored area) or to the level of pollution of the area including thecharacterization of the polluting substances or the road characteristics(ice presence, etc.). Once more, non-repetitive messages conveyinformative content proper beyond the mere fact that the message issent/received.

In the fourth exemplary application scenario discussed in the foregoing(is a “smart” street lighting system), the illumination controller ICmay send a repetitive message of the form “lights switched-on” to thelampposts LP1, LP2, . . . , LPk, . . . , LPn, with the same messagepossibly sent both for activating and maintaining street lighting.Again, if the message is sent periodically, absence of the repetitivemessage after a certain period may indicate that lighting should beturned-off. Once again, these are messages whose informative content isessentially related to the fact that they are sent (and received).

Conversely, non-repetitive messages may be variable in time and contentsand include, for instance, environment light monitoring and sensing ofcar traveling through the street in order to optimize the light powerand the illumination energy consumption. Once more, non-repetitivemessages convey informative content proper beyond the mere fact that themessage is sent/received.

One or more embodiments may comprise “dual-protocol” modem circuits asexemplified in FIG. 2 and including:

a first circuit section 101 configured to use a first physicalcommunication protocol (say, Protocol 1) for sending and/or receivingrepetitive messages, and

a second circuit section 102 configured to use a second physicalcommunication protocol (say, Protocol 2) for sending and/or receivingnon-repetitive messages.

Such a dual-protocol modem 10, including a first section 101 operatingwith a first protocol (Protocol 1) and a second section 102 operatingwith a second protocol (Protocol 2), can be devised, designed andrealized—on the basis of the disclosure of exemplary embodiments asprovided herein—by relying on principles and criteria which are per seknown to those of skill in the art. This makes it unnecessary to providea more detailed description herein.

One or more embodiments may be based on the recognition that:

repetitive messages are intended and configured to be repeated over timewith the same form or contents: as noted, the information conveyed bythese messages is primarily related to the fact that these messages aresent/received (or not);

non-repetitive messages are intended and configured to take a differentform or convey different contents over time: as noted, the informationconveyed by these messages is primarily related to the actualcontents/information conveyed thereby.

In that respect, it will be appreciated that even non-repetitivemessages may be (temporarily) sent with identical contents a number oftimes in a row: this may be the case, for instance, of a parameter (forinstance, temperature) remaining constant over two or more subsequenttransmissions of the associated non-repetitive message or ofre-transmission of a same non-repetitive message in case of unsuccessfulcommunication. That is, the non-repetitive nature of a message asconsidered herein is primarily determined by—the capability—of such amessage to convey different, variable information contents over time.

Stated otherwise:

repetitive messages are repeatedly sent as invariable, (always)identical messages over time,

non-repetitive are sent as variable messages, adapted (and expected) tovary over time.

Also, as used herein, “protocol” is conformant to the conventional“classical” definition as provided athttps://www.britannica.com/technology/protocol-computer-science, that isa set of rules or procedures for sending data between electronicdevices, such as computers.

Throughout this description of exemplary embodiments, reference is madefor simplicity and ease of explanation to protocols (Protocol 1,Protocol 2) essentially identified and distinguished from each other dueto the modulation adopted, for instance S-FSK and PSK or QAM,respectively.

Those of skill in the art will otherwise appreciate that, in one or moreembodiments, Protocol 1 and Protocol 2 may be identified anddistinguished from each other (only or also) for other features, suchas—just to mention two by way of example—word length and/or encoding.

In one or more embodiments, the second physical communication protocol(Protocol 2) may be a protocol that in the general case is deemed to beparticularly suited for use in a certain context (for instance, becauseit offers generally better communication performance, is more flexible,etc.).

Conversely, in one or more embodiments, the first physical communicationprotocol (Protocol 1) may be a protocol that, while tailored to supportrepetitive messages, may be less performant in general (weakercommunication characteristics) or less flexible (for instance because itonly supports transmission of a limited number of bits). In particularscenarios (the S-FSK capabilities with in-band narrow band interfererdiscussed in the foregoing may be a case in point) the first physicalcommunication protocol (Protocol 1) may however offer appreciableadvantages compared to Protocol 2.

In various operational contexts as those presented—just by way ofpossible examples—in FIGS. 3 to 10, adopting the expectedly “lessperformant” Protocol 1 for repetitive messages may end up by providingimproved performance of the whole process of exchanging both repetitivemessages (using Protocol 1) and non-repetitive messages (using Protocol2), with the assumed drawbacks or limitations of Protocol 1 compared toProtocol 2 being s somehow absorbed.

Even without wishing to be bound to any specific theory in that respect,a possible reason for this may lie in that message repetition maysomehow palliate the drawbacks/limitations of Protocol 1, thus improvingthe performance level of Protocol 1.

By way of—tentative—explanation, one may consider the common practice ofencoding information sent over communication channels.

Channel encoding is a procedure wherein, in order to protect a messagefrom the effect of channel attenuation and selectivity and noise,controlled redundancy is added by the sender to a message.

For instance, channel encoding can be represented by the followingequation:

I=(b ₀ , b ₁ , . . . b _(n))=>C=(c ₀ , c ₁ , . . . , c _(m))

where:

I is the original information to be transmitted and b_(j) are bits,j=0,1, . . . , n,

C is the encoded information where c_(k) are bits that depend on I andk=0,1, . . . , m with m>n.

At the receiver, the added redundancy is used to correct the errorsintroduced by the channel and noise.

As is well known to those of skill in the art, there are many ways toadd redundancy, for instance an element of C may be the linearcombination of some elements of I. A simple method to add redundancy isconsidering a repetition code that can be obtained by

I=(b ₀ , b ₁ , . . . b _(n))=>C=(b ₀ , b ₁ , . . . b _(n) , n ₀ ,b ₁ , .. . b _(n) , . . . , b ₀ , b ₁ , . . . b _(n))

i.e., the information I is repeated many times according to a certainrepetition factor r.

The benefit of coding may be measured, for instance, in terms of SNRgain, i.e. the capability to handle a lower signal-to-noise ratio at thereceiver. For instance, repetition codes in a flat channel with additivewhite Gaussian noise (AWGN) may exhibit a SNR gain which increases withthe increase of the repetition factor r:

If r=2, the SNR gain is 3 dB

If r=4, the SNR gain is 6 dB

In general,

If r=m, the SNR gain is 10*log₁₀(m) dB

where log₁₀, is the logarithm with base 10.

On the other hand, repetition coding—by itself, in general—may beregarded as (largely) inefficient insofar as it may drastically reducethroughput.

At least to some extent, one or more embodiments may be regarded astaking advantage of repetition to render a generally less robustprotocol (Protocol 1) at least as robust as another protocol (Protocol2). For instance a Protocol 1 based upon S-FSK modulation may becomeeven more robust than a Protocol 2 based on PSK or QAM.

As noted, repetition coding is however inefficient per se, due to apossible throughput reduction.

One or more embodiments as exemplified herein somehow go against such ageneral appreciation by noting that, in various operational contexts asthose presented—just by way of possible examples—in FIGS. 3 to 10, theinefficiency related of repetition codes is encompassed (that is,“absorbed”) by using the less performing protocol, namely Protocol 1,for messages that are by themselves repetitive, that is messagesrepeatedly sent as invariable, (always) identical signals over time.

For instance, knowing that these messages are repeated identically (e.g.as confirmatory messages of a continuing condition or state) mayfacilitate—especially if these messages are repeated with a certain,fixed period—a “Protocol 1” receiver in increasing receiver robustnessby combining various occurrences of (identical) information receivedrepeatedly.

For instance, in the case of repetition taking place with a givenperiod, the receiver may synchronize on that period—by resorting toknown techniques, such as e.g. PLL tracking—and search the expectedinformation (only) during particular time windows.

Also, the fact that repetitive messages are repeatedly sent asinvariable, identical signals over time may facilitate receiveroperation: the receiver may in fact already know what such repeatedsignals (expectedly selected from a set including few signals, possiblyeven just one signal) “will look like”, with the ensuing possibility ofadopting, for instance, matched filter processing or the like.

The Protocol 1 receiver may thus be relieved of the burden ofunnecessary activity between a message and its repetition.

Also, as noted previously, Protocol 1 may exhibit—in certaincircumstances, e.g. in-band interferers—certain intrinsic advantagescompared to Protocol 2, so that Protocol 1 can be in fact used also forimportant messages (that are repetitive).

This is because Protocol 1 may see its robustness improved in comparisonwith Protocol 2 by benefitting from message repetition, while alsopossibly retaining certain original advantages in particular scenarios.At the same time, original advantages of Protocol 2 are preserved insending non-repetitive messages insofar as they are unaffected by theadoption of Protocol 1 for repetitive messages.

One or more embodiments may facilitate using, for repetitive messages, aprotocol (Protocol 1) which does not involve a large bandwidth and/or ahigh signal power to be sent and, particularly, a protocol which—incomparison to Protocol 2—involves a narrower bandwidth and/or a lowersignal power to be sent, which may be (even largely) beneficial in termsof communication resources. For instance, in one or more embodimentsProtocol 1 may be selected as a protocol involving a low power, thusreducing power absorption, which may be suited for transmission e.g.from sensors powered via harvester circuits.

This by also taking into account that, in scenarios such as thoseexemplified herein, repetitive messages/signals may be predominant (evenlargely) over non-repetitive messages/signals, in that repetitivemessages/signals may be transmitted most of the time (e.g. at relativelyshort intervals from one another) and non-repetitive messages/signalstransmitted less frequently (e.g. at relatively long intervals from oneanother), if not only seldom or rarely.

For instance, in one or more embodiments, Protocol 1 may be asingle-carrier protocol (that is, a protocol involving signaltransmission over a single carrier), while Protocol 2 may be amulti-carrier protocol (that is, a protocol involving signaltransmission over a two or more carriers).

Also, in one or more embodiments, Protocol 1 (used for repetitivemessages) and Protocol 2 (used for non-repetitive messages) maycoexist—that is can be both supported—on a same carrier or system byresorting to various solutions known to those of skill in the art: TimeDivision Multiplexing (TDM) or Frequency Division Multiplexing (FDM) areexemplary of such solutions.

Turning again to FIGS. 3 to 10, in the first exemplary applicationscenario considered in the foregoing (a photovoltaic power generationsystem comprising—in a manner known per se—an inverter I and a pluralityof solar panels SP1, SP2, . . . , SPk) Protocol 1 may be used by a“dual-protocol” modem 10I in an communication unit in the inverter I toperiodically send to the modems 10SP1, 10SP2, . . . , 10SPk in thephotovoltaic panels SP1, SP2, . . . , SPk repetitive messages withsemantics: “power production active” as schematically represented inFIG. 3.

Such a repetitive message can be identically sent both for starting andfor continuing power production, with the direction (command) to haltpower production possibly conveyed by discontinuing the periodicaltransmission of that signal.

Of course, such a repetitive message may convey the same semantics witha different arrangement (like “power injection uninterrupted”) selectedout of a gamut of possible options.

As schematically represented in FIG. 4, Protocol 2 may be used by theinverter modem 10I and panel modems 10SP1, 10SP2, . . . , 10SPk forexchanging, e.g. panel temperature statistics, panel voltage data orpanel inclination to optimize solar power capturing or similarquantities that may vary several times and with different granularityduring the day and that deserve monitoring.

In one or more embodiments, Protocol 1 may have a fixed number of bitssent while Protocol 2 may be more “general purpose”, for instance withvariable granularity with the number of bits sent.

Also, Protocol 1 may have a limited set of possible messages/messagelengths out of which the repetitive messages can be selected.

In one or more embodiments, Protocol 2 may be a more sophisticatedprotocol admitting a wide variety of possible non-repetitive messages tochoose from, possibly with variable message lengths.

By way of example, Protocol 1 may be based on a first modulation, forinstance, S-FSK modulation and Protocol 2 may be based on a secondmodulation, for instance PSK or QAM modulations.

Also, Protocol 1 may be devised for uni-directional communication (forinstance, only from the inverter modem 10I to the panel modems 10SP1,10SP2, . . . , 10SPk).

Conversely, Protocol 2 may be devised for bi-directional communication,e.g. with panel modems 10SP1, 10SP2, . . . , 10SPk capable of answeringrequests from the inverter 10I or simply acknowledging the reception ofinverter messages. Also, as schematically represented in FIG. 4,Protocol 2 may facilitate making exchange of messages selective, e.g.with messages from the inverter modem I10I sent individually (only) toselected ones of the panel modems, e.g. 10SP3 and 10SPk.

As noted, both Protocol 1 and Protocol 2 messages may be carried byDC-power lines from the solar panels to the inverter.

The second exemplary application scenario discussed in the foregoingcomprises a house monitoring system of a house property HP including—ina manner known per se—house monitoring units HM1, HM2, . . . , HMn aswell as a local unit LU in the house possibly communicating with acentral unit CU, e.g. at the police department or a (private)surveillance center SC.

In one or more embodiments, these units may be equipped with respective“dual-protocol” modems (not expressly visible in the figures forsimplicity).

For instance, as exemplified in FIG. 5, the modems in the housemonitoring units HM1, HM2, . . . , HMn may use Protocol 1 to send arepetitive message, that, by example, may have the semantics “all OK, nohousebreaking detected” to the modem in the local unit LU.

For instance, if the message is sent using a periodicity known both atthe sender and at the receiver, the receiver in the local unit LU maydetect that something is not OK if the message is not received at theexpected time (the expected time may be different for the differenthouse monitoring units HM1, HM2, . . . , HMn).

The modem in the local unit LU may use Protocol 1 to run a similarrepetitive message communication with a modem in the central unit CU. Asnoted, the central unit CU may be located at a police department or at aprivate surveillance center, thus facilitating generating real timealarms (as exemplified in FIG. 5).

As exemplified in FIG. 6, Protocol 2 may be used instead in connectionwith other messages that are variable over time and can be used toconvey information content including, without limitation, externaland/or internal house atmosphere monitoring (temperature, pressure).This time—variable information can be used, for instance, to supporthouse air-conditioning or to facilitate soil moisture monitoring toprovide the proper irrigation to an external garden, internal controland use of the household appliances.

In one or more embodiments, Protocol 1 may have a fixed number of bitssent while Protocol 2 may be more general purpose, for instance withvariable granularity with the number of sent bits.

Again, Protocol 1 may have a limited set of possible messages/messagelengths out of which the repetitive messages can be selected.

In one or more embodiments, Protocol 2 may be a more sophisticatedprotocol admitting a wide variety of possible non-repetitive messages tochoose from, possibly with variable message lengths.

By way of example, Protocol 1 may be based on a first modulation, forinstance, S-FSK modulation and Protocol 2 may be based on a secondmodulation, for instance PSK or QAM modulations.

Also, Protocol 1 may be devised for uni-directional communication fromthe house monitoring units HM1, HM2, . . . , HMn to the local unit LUand/or from the local unit LU to the central unit CU.

Protocol 2 may accommodate bi-directional communication, with the housemonitoring units HM1, HM2, . . . , HMn and the local unit LU exchangingfor instance domotics messages.

One or more embodiments may contemplate using Protocol 1 for repetitivemessages from the local unit LU to the house monitoring units HM1, HM2,. . . , HMn, an example being a message with semantics “surveillancecamera(s) active”, which again may be used both to turn on the camera(s)addressed and to keep it/them turned on.

For instance, the modems in the monitoring units HM1, HM2, . . . , HMn,may use an in-home power line to communicate with the modem in the localunit LU.

The third exemplary application scenario considered in the foregoingcomprises a traffic monitoring system including—again in a manner knownper se—various traffic observation points (cameras, for examples) 1, 2,3, . . . , S and a central traffic monitoring unit or center C.

In one or more embodiments, these units may be equipped with respective“dual-protocol” modems (not expressly visible in the figures forsimplicity).

In one or more embodiments, as exemplified in FIG. 7, Protocol 1 can beused by the modems in the traffic observation points 1, 2, 3, . . . , Sto send repetitive messages such as “there is no car accident” or “thetraffic unit—for instance traffic lights—are functioning as expected” tothe central unit C.

In one or more embodiments, as exemplified in FIG. 8, communication withvariable messages in time and content may take place by using Protocol2. These variable messages may relate, for instance, to certain noiselevel parameters (these cam be indicative of the car concentration inthe urban traffic monitored area) or to a level of pollution of thearea, possibly including the characterization of the pollutingsubstances or the road characteristics (ice presence, etc.).

Once more, in one or more embodiments, Protocol 1 may have a fixednumber of bits sent while Protocol 2 may be more general purpose, forinstance with variable granularity with the number of sent bits.

Again, Protocol 1 may have a limited set of possible messages/messagelengths out of which the repetitive messages can be selected.

In one or more embodiments, Protocol 2 may be a more sophisticatedprotocol admitting a wide variety of possible non-repetitive messages tochoose from, possibly with variable message lengths.

By way of example, Protocol 1 may be based on a first modulation, forinstance, S-FSK modulation and Protocol 2 may be based on a secondmodulation, for instance PSK or QAM modulations.

Also, Protocol 1 may be devised for uni-directional communication fromthe traffic observation points 1,2, . . . , S to the central unit.

Protocol 2 may accommodate bi-directional communication, e.g. with thecentral unit C gathering road and car traffic parameters and possiblysending information to be transferred to signs/displays to assistdrivers.

The fourth exemplary application scenario considered in the foregoingcomprises a “smart” street lighting system, including—again in a mannerknown per se—a number of light radiation sources (e.g. lamp posts) LP1,LP2, . . . , LPk, . . . , LPn controllable by an illumination controllerIC in illuminating a street, a road, a square, and so on.

Also in this scenario, the light radiation sources LP1, LP2, . . . ,LPk, . . . , LPn and the controller IC In one or more embodiments may beequipped with respective “dual-protocol” modems (again not expresslyvisible in the figures for simplicity).

In one or more embodiments, as exemplified in FIG. 9, the modem in theillumination controller IC can use Protocol 1 to send a repetitivemessage of the form “light source activated” or a message with similarsemantics to the modems in the lampposts LP1, LP2, . . . , LPk, . . . ,LPn.

In one or more embodiments, such a message can be sent with a regulartime periodicity starting from a determined hour of the day (forinstance after sunset).

In one or more embodiments, as exemplified in FIG. 10, Protocol 2 can beused by the modems in the illumination controller IC and in thelampposts LP1, LP2, . . . , LPk, . . . , LPn, for exchanging messagesthat are variable in time and content and may include environment lightmonitoring and sensing of car traveling through the street in order tooptimize the light power and the illumination energy consumption.

Protocol 2 may also facilitate selective communication of theillumination controller IC even with selected ones of the lampposts, forinstance, as exemplified in FIG. 10, with LP2 by excluding LP1.

Once more, Protocol 1 may have a limited set of possiblemessages/message lengths out of which the repetitive messages can beselected.

In one or more embodiments, Protocol 2 may be a more sophisticatedprotocol admitting a wide variety of possible non-repetitive messages tochoose from, possibly with variable message lengths.

By way of example, Protocol 1 may be based on a first modulation, forinstance, S-FSK modulation and Protocol 2 may be based on a secondmodulation, for instance PSK or QAM modulations.

Also, Protocol 1 may be devised for uni-directional communication fromthe illumination controller IC to the lampposts LP1, LP2, . . . , LPk, .. . , LPn.

Conversely, Protocol 2 may accommodate bi-directional communication,with the illumination controller IC and the lampposts LP1, LP2, . . . ,LPk, . . . , LPn, exchanging more sophisticated information, possiblyrelated to sensors installed on the lampposts LP1, LP2, . . . , LPk, . .. , LPn. The modem in the illumination controller IC and the modems inthe lampposts LP1, LP2, . . . , LPk, . . . , LPn may be connected usingthe already existing power line backbone of the lighting system.

In one or more embodiments, a method may comprise:

providing a communication circuit (for instance, a modem such as 10) fortransmitting (for instance, sending and/or receiving) signals conveyinginformation messages, the communication circuit supporting a firstcommunication protocol (for instance, portion lot in FIG. 2) and asecond comm cation protocol (for instance, portion 102 in FIG. 2), thesecond communication protocol different from the first communicationprotocol,

Including in the signals first signals conveying first informationmessages and second signals conveying second informationessages, thefirst information messages comprise at least one repetitive essagehaving fixed repeated content (for instance: “all is OK”, “continue todo it”, “I am here.”, “keep synchronized”) and the secondinformation/messages comprise at least one non-repetitive essage havingvariable content (for instance, temperature pressure, statistics,concentration index, cars travelling in street), and

transmitting the first signals and the second signals via thecommunication circuit using the first communication protocol for thefirst signals and the second communication protocol for the secondsignals.

In one or more embodiments, the first communication protocol and thesecond communication protocol may comprise different modulations for thefirst signals and the second signals, respectively.

In one or more embodiments, the first communication protocol maycomprise FSK modulation, optionally S-FSK modulation.

In one or more embodiments, the second communication protocol maycomprise modulation selected out of PSK modulation and QAM modulation.

In one or more embodiments:

the first communication protocol may have a longest message lengthshorter than the longest message length of the second communicationprotocol, and/or

the first communication protocol and the second communication protocolmay comprise a single-carrier protocol and a multi-carrier protocol,respectively, and/or

the first communication protocol may have a bandwidth occupancy narrowerthan the bandwidth occupancy of the second communication protocol.

One or more embodiments may comprise transmitting the first signals andthe second signals via the communication circuit using for the firstcommunication protocol a signal strength lower than the signal strengthused for the second communication protocol.

One or more embodiments may comprise including in the signals a set ofthe first signals and a set of the second signals, wherein the set ofthe first signals is less numerous than the set of the second signals.

One or more embodiments may comprise transmitting the first signals andthe second signals via the communication circuit via time domain and/orfrequency domain multiplexing.

In one or more embodiments, transmitting the first signals and thesecond signals via the communication circuit may comprise interleavingthe first signals and the second signals.

One or more embodiments may comprise transmitting the first signals viathe communication circuit using the first communication protocol with afixed repetition rate.

In one or more embodiments, a device (for instance, a modem such as 10)may comprise a communication circuit configured (see, for instance, thetwo circuit sections 101 and 102 of the modem 10 of FIG. 2) tocommunicate—that is, send and/or receive—first signals conveying firstinformation messages and second signals conveying second informationmessages, wherein the first information messages comprise at least onerepetitive message having fixed repeated content and the secondinformation messages comprise at least one non-repetitive message havingvariable content, the communication circuit configured to support afirst communication protocol and a second communication protocol, thesecond communication protocol different from the first communicationprotocol, the device configured to operate with the method of one ormore embodiments.

In one or more embodiments, the device may comprise a modem.

In one or more embodiments, a communication system, may comprise atleast one first node (for instance, I, LU, C, IC, or, respectively, SP1,SP2, . . . , SPk; HM1, HM2, . . . , HMn; 1, 2, . . . , S; LP1, LP2, . .. , LPk, . . . , LPn) and at least one second node (for instance, SP1,SP2, . . . , SPk; HM1, HM2, . . . , HMn; 1, 2, . . . , S; LP1, LP2, . .. , LPk, . . . , LPn or, respectively, I, LU, C, IC,), the at least onefirst node and at least one second node equipped with a device accordingto one or more embodiments.

In one or more embodiments, a method of operating a system according toone or more embodiments may comprise:

sending uni-directional first signals using the first communicationprotocol towards the at least one first node from the at least onesecond node (for instance towards I, LU, C, IC from SP1, SP2, . . . ,SPk; HM1, HM2, . . . , HMn; 1, 2, . . . , S; LP1, LP2, . . . , LPk, . .. , LPn or, vice-versa, towards SP1, SP2, . . . , SPk; HM1, HM2, . . . ,HMn; 1, 2, . . . , S; LP1, LP2, . . . , LPk, . . . , LPn from I, LU, C,IC),

exchanging bi-directional second signals using the second communicationprotocol between the at least one first node and the at least one secondnode.

One or more embodiments may relate to a combined (for instance,dual-protocol) communication signal comprising (for instance, in afrequency-domain or time-domain multiplexing scheme, e.g. byinterleaving the first signals and the second signals) first signalsconveying first information messages and second signals conveying secondinformation messages, wherein the first information messages comprise atleast one repetitive message having fixed repeated content and thesecond information messages comprise at least one non-repetitive messagehaving variable content, wherein the combined communication signalcomprises a multi-protocol signal including a first communicationprotocol for the first signals and a second communication protocol forthe second signals, the second communication protocol different from thefirst communication protocol.

Without prejudice to the underlying principles, the details andembodiments may vary, even significantly, with respect to what has beendescribed by way of example only, without departing from the extent ofprotection.

The extent of protection is determined by the annexed claims.

What is claimed is:
 1. A method of operating a communication circuitsupporting a first communication protocol and a second communicationprotocol that is different from the first communication protocol, themethod comprising: generating a plurality of signals including firstsignals conveying first information messages and second signalsconveying second information messages, wherein the first informationmessages comprise a repetitive message having fixed repeated content andthe second information messages comprise a non-repetitive message havingvariable content; and transmitting the first signals and the secondsignals via the communication circuit using the first communicationprotocol for the first signals and the second communication protocol forthe second signals.
 2. The method of claim 1, wherein the firstcommunication protocol and the second communication protocol comprisedifferent modulations for the first signals and the second signals,respectively.
 3. The method of claim 2, wherein the first communicationprotocol comprises FSK modulation.
 4. The method of claim 2, wherein thefirst communication protocol comprises spread frequency shift keying(S-FSK) modulation.
 5. The method of claim 2, wherein the secondcommunication protocol comprises PSK modulation.
 6. The method of claim2, wherein the second communication protocol comprises QAM modulation.7. The method of claim 2, wherein the first communication protocolcomprises FSK modulation and wherein the second communication protocolcomprises PSK modulation or QAM modulation.
 8. The method of claim 1,wherein the first communication protocol has a longest message lengthshorter than the longest message length of the second communicationprotocol.
 9. The method of claim 1, wherein the first communicationprotocol comprises a single-carrier protocol and the secondcommunication protocol comprises a multi-carrier protocol.
 10. Themethod of claim 1, wherein the first communication protocol has abandwidth occupancy narrower than the bandwidth occupancy of the secondcommunication protocol.
 11. The method of claim 1, wherein transmittingthe first signals and the second signals via the communication circuitcomprises using a first signal strength for the first communicationprotocol and a second signal strength for the second communicationprotocol, the first signal strength being lower than the second signalstrength.
 12. The method of claim 1, wherein generating the plurality ofsignals comprises including a set of the first signals and a set of thesecond signals, wherein the set of the first signals is less numerousthan the set of the second signals.
 13. The method of claim 1, whereintransmitting the first signals and the second signals comprisestransmitting the first signals and the second signals via thecommunication circuit via time domain multiplexing.
 14. The method ofclaim 1, wherein transmitting the first signals and the second signalscomprises transmitting the first signals and the second signals via thecommunication circuit via frequency domain multiplexing.
 15. The methodof claim 1, wherein transmitting the first signals and the secondsignals comprises interleaving the first signals and the second signals.16. The method of claim 1, wherein transmitting the first signalscomprises transmitting the first signals via the communication circuitusing the first communication protocol with a fixed repetition rate. 17.A device, comprising: a communication circuit configured to communicatefirst signals conveying first information messages and second signalsconveying second information messages, wherein the first informationmessages comprise a repetitive message having fixed repeated content andthe second information messages comprise a non-repetitive message havingvariable content, the communication circuit configured to support afirst communication protocol and a second communication protocol that isdifferent than the first communication protocol so that, duringoperation, the first communication protocol is used for the firstsignals and the second communication protocol is used for the secondsignals.
 18. The device of claim 17, wherein the device comprises amodem.
 19. A method of communicating, the method comprising: sendinguni-directional first signals toward a communication signal node using afirst communication protocol, wherein the uni-directional first signalsinclude first information messages that comprise a repetitive messagehaving fixed repeated content; and exchanging bi-directional secondsignals with the communication signal node using a second communicationprotocol that is different than the first communication protocol,wherein the bi-directional second signals include second informationmessages that comprise a non-repetitive message having variable content.20. The method of claim 19, wherein the first communication protocol andthe second communication protocol comprise different modulations for thefirst signals and the second signals, respectively.
 21. The method ofclaim 20, wherein the first communication protocol comprises FSKmodulation and wherein the second communication protocol comprises PSKmodulation or QAM modulation.
 22. The method of claim 19, wherein thefirst communication protocol has a longest message length shorter thanthe longest message length of the second communication protocol.
 23. Themethod of claim 19, wherein the first communication protocol comprises asingle-carrier protocol and the second communication protocol comprisesa multi-carrier protocol.
 24. The method of claim 19, wherein the firstcommunication protocol has a bandwidth occupancy narrower than thebandwidth occupancy of the second communication protocol.